Analysis of the push-pull signal in the multi-level run-length limited read-only disc

Multi-level run-length limited (ML-RLL) recording technology can increase the capacity of the read-only disc without changing the optical and mechanical units. The characteristic of the push-pull signal of the multi-level run-length limited read-only disc is analyzed and compared with that of the conventional DVD read-only disc. Experimental results show the effect of the variation of pit depth is more than other parameters and the peak-to-peak amplitude of the push-pull signal in the ML-RLL read-only disc is about 2.9 times of that in the DVD read-only disc while the variance is nearly 3.2 times. The push-pull method in the ML-RLL read-only disc is more sensitive than that in the conventional DVD read-only disc.